After-market shocks only seem available in MM tune. 2015 Giant Anthem's use a LM tune. Accordingly, the MM shock needs a revalve to LM tune specs.
Marmoto has a comparison between MM and LL tunes here.
| M rebound stack | L rebound stack | Notes |
|---|---|---|
| 19mm x 0.15 | 19mm x 0.15 | |
| 16mm x 0.15 | 16mm x 0.10 | Inner shim for ring shim |
| 16.4mm x 0.3 | 16.4mm x 0.3 | ring shim |
| 19mm x 0.15 | 19mm x 0.15 | |
| 19mm x 0.15 | ||
| 11mm x 0.3 | 11mm x 0.3 | clamp |
Comparing the two HSR (high speed rebound) stacks we can see that the L tune is more preloaded (0.2mm preload compared to 0.15mm preload) but a faster overall stack (one less 19mm x 0.15 shim). The L HSR tune is more digressive and flows more oil under HSR events. It looks like Rockshox are trying to achieve the same damping coefficient on LSR events with the L and M stacks, but faster HSR on the L stack. See Ring shim stack preload tuning.
Part number for "tune assy, Monarch XX/RL Reb-Low/Comp-Mid (CF-97lbs), LF-430, B1" is 11.4118.023.029
Insides of a Monarch XX 2014 - fotki.yandex.ru/users/olegn/album/148101/